PERIODICAL AND VARIABLE STARS.

It was upon a lovely evening, when off the coast of South America, ready to slip across by the side-help of the South-east Trades to the Cape¹ of Good Hope, that Mr. Marple found his son at his old post.

“Now then,” said he, “my star-gazing boy, are you quite sure that none of them have run away since last night?

I am not sure of that, father; for ever since you proved that the Fixed² stars were not fixed, I think I might some day find a bright friend gone on a visit to another universe somewhere; perhaps, getting into such agreeable society as to have no wish to come back again to our visible universe; or, maybe, to pop back again in his place.

It so happens, James, that what you have imagined, really takes place. Some stars do really disappear, to return, or not; and others,[Pg 58] wholly strangers to us, come within observation.

That is the queerest thing you have told me yet. What droll³ fellows the stars are, after all! How they do wriggle⁴ about, polkaing here, doubling there, and fielding about like boys at cricket. I shall never be surprised at any funny trick you ascribe to them.

To begin with the Variable stars, of which there are known about one hundred. There is Mira, which is invisible five months in the year. It goes and comes again.

Where could it have got to?

Some think it revolving⁵ round a dark object; and, of course, becoming invisible when on the other side from us. One passes through three magnitudes in one month.

But I must give you the history of such a curious star in the Whale. For two weeks you might see it a noble star of the second magnitude. It gradually dims, till it goes fairly out of sight in three months. For five weeks you see nothing of it. It then reappears. Altogether it seems to have a revolution of 322 days; and is, therefore, one of the Periodical stars.

I should call it a variable periodical.

There is another in Cepheus, which grows to its full light in thirty-eight hours only. There is one in the Lyre taking ninety-one hours. Some fancy that the dark appearance may be owing to huge spots on the suns coming into view as the suns turn round. But there is still another sort of star—the Temporary.

[Pg 59]Do they come and have a look at us in their birth, and then disappear never to return?

I will tell you the history of one. In 1572 an astronomer⁶ saw it shining in the daytime. He could not find it in his star catalogue at home. Day after day it grew brighter and brighter, till it blazed far more than either Sirius or Jupiter, and could be plainly seen in the noontide sun. It then grew dim gradually, and in two years went away altogether, without returning since.

That is temporary, and no mistake. But still I guess they will find him turning up some day and becoming a regular Periodical.

There is a wonderful star, Argus, in Argo. Two hundred years ago it was of the fourth magnitude only. In 1834, Sir John Herschel, when at the Cape of Good Hope, found it a second magnitude. The light was three times stronger at the end of 1837. Next month it was brighter than any star here but Sirius. It faded awhile, and then increased, till, in 1844, it was equal to Sirius itself.

Have they looked over the old catalogues of stars, made, as you told me, two thousand years ago, just to see what ones have dropped out of sight, father?

Yes, and several have disappeared which were on that list.”

1 cape   

n.海角，岬；披肩，短披风

参考例句：

• I long for a trip to the Cape of Good Hope.我渴望到好望角去旅行。
• She was wearing a cape over her dress.她在外套上披着一件披肩。

2 fixed   

adj.固定的，不变的，准备好的；(计算机)固定的

参考例句：

• Have you two fixed on a date for the wedding yet?你们俩选定婚期了吗？
• Once the aim is fixed,we should not change it arbitrarily.目标一旦确定，我们就不应该随意改变。

3 droll   

adj.古怪的，好笑的

参考例句：

• The band have a droll sense of humour.这个乐队有一种滑稽古怪的幽默感。
• He looked at her with a droll sort of awakening.他用一种古怪的如梦方醒的神情看着她.

4 wriggle   

v./n.蠕动，扭动；蜿蜒

参考例句：

• I've got an appointment I can't wriggle out of.我有个推脱不掉的约会。
• Children wriggle themselves when they are bored.小孩子感到厌烦时就会扭动他们的身体。

5 revolving   

adj.旋转的，轮转式的；循环的v.（使）旋转( revolve的现在分词 )；细想

参考例句：

• The theatre has a revolving stage. 剧院有一个旋转舞台。
• The company became a revolving-door workplace. 这家公司成了工作的中转站。

6 astronomer   

n.天文学家

参考例句：

• A new star attracted the notice of the astronomer.新发现的一颗星引起了那位天文学家的注意。
• He is reputed to have been a good astronomer.他以一个优秀的天文学者闻名于世。